Preeclampsia remains one of the pressing challenges in modern obstetrics, by largely determining the structure of maternal and perinatal morbidity and mortality. The lack of a unifying theory of the etiopathogenesis of preeclampsia hampers its diagnosis, evaluation of its severity, and implementation of therapeutic measures. The data available in the literature suggest that lipid peroxidation processes are impaired in the presence of antioxidant deficiency as a trigger of preeclampsia. Activated lipid peroxidation gives rise to irreversible damage to the membrane structures, altered blood rheological properties, and impaired microcirculation. At this point, there is inhibition of the components of the antioxidant defense system: the activity of enzymatic antioxidants and the level of nonenzymatic ones are decreased. The given review shows the rate of free radical oxidation and the incompetence of antioxidant defense in preeclampsia. The change in the fine molecular mechanisms of regulation, which occurs in a pregnant women before the clinical manifestation of preeclampsia, accounts for the need to monitor lipid oxidation and antioxidant defense processes when following up the patients at high risk for preeclampsia for prediction, diagnosis, control, and therapy. The authors declare no conflicts of interest.